Conventional gas turbines generally include three sections: a compressor section, a combustor section and a turbine section. The compressor section compresses ambient air, and provides that compressed air to the combustion section where it is combined with fuel to generate a heated working fluid (gas). The heated gas is provided to the turbine section, where it impacts turbine blades to drive rotation of the turbine rotor shaft.
In the turbine section, sets of rotating blades are attached to a rotor, and sets of stationary nozzles are dispersed between each adjacent set of rotating blades for directing working fluid (gas) to the rotating blades. Each pairing of rotating blades and stationary nozzles are conventionally referred to as a turbine stage. The high-pressure, high-temperature environment within the turbine section can cause mechanical wear-and-tear on the blades and nozzles, requiring periodic, and in some cases, scheduled maintenance. Because the blades and nozzles reside within a turbine housing with small clearances between components, it can be difficult to access those blades and nozzles for scheduled or other maintenance. For example, the nozzles are retained within a ring that surrounds the rotor, and are loaded into (and unloaded out of) the ring and pinned into position next to an adjacent nozzle. Additionally, seals for each nozzle are individually loaded/unloaded with those nozzles, further complicating the maintenance process.
Conventional approaches for loading and/or unloading these nozzles involve loading each individual nozzle segment from above a horizontal joint surface of the turbine casing and lowering it to its adjacent part using rigging and/or other manual approaches. This process can be time-consuming and costly.